When a five million pound granite slab fell from one of Yosemite’s most renowned cliffs last week, several days of storms meant no one was around to see it. But on 5 July, when a pair of climbers on Half Dome’s north-west face called their friend in the valley to say they were stuck below a missing ledge, word spread quickly through the tight-knit climbing community.

Now the race is on to be the first to remap some of the most spectacular and influential routes across the new rock face in Yosemite.

While the 1,500-meter cliff lost a section of rock about 60 meters high, that size of flake is by no means uncommon in the park, which is constantly being shaped by chips and boulders peeling off the 100m-year-old formations.

It might even seem puny relative to the largest such incident, at the Three Brothers rock formation, in 1987. Just down the valley from Half Dome, an unknown cause sent 600,000 cubic meters of rock barrelling through thick conifers and down across the Merced River. By contrast, the Half Dome flake left just about 800 cubic meters of talus at the cliff base.

Rockfall the scale of last week’s happens about once a year in Yosemite, presenting a constant potential hazard to visitors. In 2008, a massive rockfall below nearby Glacier Point forced the closing and relocation of 276 cabins at visitor outpost Curry Village.

This latest release is significant not because of its size but because of its location.

“What makes it interesting is that it came right off one of the two most historic routes in Yosemite Valley,” says professional climber Cedar Wright, who worked for Yosemite Search and Rescue for five years and was the first to climb many of Yosemite’s most difficult routes. Only the Nose on El Capitan rivals in popularity and significance.

The Half Dome flake ripped a hole in the Robbins traverse, named after climbing pioneer Royal Robbins, who first completed the route in 1957, the hardest completed climb in the US at that time.

Although no one has taken a thorough look at the new rock face yet, due to ongoing rain, it seems likely that the route will need new bolts for climbing ropes, which most climbers rely on to safeguard against falls.

“It’s a classic. [And whoever does it] will get to put their name on that route,” says Wright, who is based in Boulder, Colorado, and last visited Yosemite in April. “I have to admit, for sure, I thought, maybe I should go out there and re-establish it.”

Wright is probably far from the only person to have that thought, considering that the route is popular and relatively accessible to non-experts.

“Everybody is of the mindset that there is going to be a race to figure out this new link,” says Yosemite chief of staff Mike Gauthier, a strong climber himself. “I think it’s going to attract people who want to be a part of this historic line.”

That race presents several potential hazards. Park rangers were able to reach the area just below the denuded rock face on Tuesday, and warned of loose rock where the flake broke free from the wall.

Days of rain, which may have triggered the break, present a continued hazard, according to park geologist Greg Stock. Climbing routes in the valley always are at risk from falling rock, which he warns is nearly impossible to predict.

“There are at least two other features that have fallen off on that route,” says Stock. “These cliffs are not static.”

Apart from physical hazards, climbing ranger Brandon Latham says re-establishing the route could threaten the character of the wall. The now smooth surface might well require a large number of bolts to be passable again. He says he has never seen anything like the damage done to such a recognizable feature.

“Looking at it the other day, the section where the rock fell off is pretty blank,” says Latham, meaning a bolt ladder might have to be installed.

A ladder would be substantially easier than what was there before. On the other hand, if a more ambitious climber were to reach the spot first, they might make the route substantially harder by placing bolts farther apart or along a more difficult line.

Gauthier says the rain is the only thing that’s keeping the route suspended in uncertainty. Otherwise, he says, motivated climbers would already be up there, scouting and re-establishing the line.

The park service leaves that work up to climbers, who are not allowed to use any sort of power tools to set bolts. It’s all done very slowly, by hand, taking anywhere from 20-45 minutes per bolt.

As a result, the shape of the route will be governed by whoever gets there first. “I think it’ll all depend on the talent of the climber who gets up there,” says Gauthier. “And I’d guess it’s going to be someone pretty motivated.”

For Wright’s part, he hopes that whoever gets there first designs it in keeping with what the route has been for many: a spectacular, moderate route that anybody with strength and basic ability can accomplish.

An unwritten set of rules govern the climbing code of conduct and dictate certain respect for the work of those who came before. “I really would like to go up there to try to re-establish the route,” says Latham. “But part of me is kind of holding back from that because … I don’t feel it’s my place to do it as a climbing ranger.”

Wright says the whole incident helps to put Yosemite climbing in perspective. Quite literally, nothing is set in stone.

“Just by being at Yosemite, you’re at risk of being buried by rockfall,” says Wright. “Even something as seemingly permanent as a cliff face in geological time is eroding away like a dirt bank.”

In the meantime, regardless of who is first up the wall, there will probably be debate about whatever style is chosen for the new section of Half Dome.

“Anyone who’s a fairly accomplished climber should be able to do that route, not just your most badass experts, I would hope,” says Wright. He adds that anything radical would be hugely controversial. “Us climbers love to get in ethical debates.”

For his part, Gauthier asks that whoever gets there first report back – and he warns climbers that failure to respect the route will be noticed. “Whatever climber does the workaround,” says Gauthier, “they should be mindful that the climbing community will be watching closely.”